Great shot of the moon, that 500mm lens is a beauty.
I got this last night with the R5, Sigma 150-600 C with 1.4x Sigma converter and the R5 set to crop mode just to see how close I could get. This shot fills my screen at full resolution, it even looks to be almost be at the same point as your shot. This was f/9, 1/640, ISO800 and 840mm, hand held, but not for long.